Steam-engine cut-off valve



(No Model.)

A. A. ACKERLY.

STEAM ENGINE GUT-OFF VALVE.

N0. 288.196. Patented Nov. 13, 1883.

' W; M. a. Qdwr u. PETERS PlwloLhlw -a hm Washing'om D. C.

Nrrnn STATES I PATENT OFFICE.

AARON A. ncnnnnv, on CHICAGO, ILLINOIS.

STEAM-ENGIN-E CUT=OFF VALVE.

SPECIFICATION forming part of Letters Patent No. 288,196, dated November 13, 1883. i Application filedApril2,18S3. (No model.)

residing at Chicago, inthe county of (look and State of Illinois, and a citizen of the United States, have invented new and useful Improvements in Steam- Engine Cut- Off Valves, of which the following is a'full description, reference being had to the accompanying drawings, in which Figure l is a vertical longitudinal section. Fig. 2 is a detail; Fig. 3, a detail. Fig. 4is a detail, showing a check-valve at the exhaustport H.

In using steam expansively as a motive power with high-pressure engines it is common to use a slide or rotary valve arranged to close the exhaust-ports at about the same time that the steam is out off, the piston during a considerable portion of its stroke working against and compressing the steam remaining in front of it in the cylinder after the exhaust ports have been closed by the valve, which remaining steam offers great resistance to the movement of the piston.

The object of my invention is to relieve the cylinder of the steam remaining therein and .in front of the piston after the exhaust-ports have been closed, thereby avoiding compression, which I accomplish by providing additional exhaust-ports and a secondary valve controlling such ports, operating substantially as hereinafter fully described.

In the drawings, A represents a steam-cylinder,

B is the piston-head, and C the piston-rod.

D is a slide-valvelocated in the steam-chest E. a, a, and b are ordinary steam inlet and exhaust ports.

F is aseconda-ry valve, consisting of two parts or heads, 0, provided with suitable packingrings, the two parts 0 being connected by a central smaller portion, d. This valve F is located in a valvechamber, G.

e e are two exhaust-passages leading from opposite ends of the cylinder to the valvechamber G, into which they open at f and g.

h h are two passages leading from the passages c a, respectively, to the opposite ends of the chamber G, for the purposeof admitting steam to such chamber to operate the valve F. H is an exhaust-port for the valve-chamber G;

I is a bridle upon one end of the valve-chamber G.

J is a rod connected with the valve F, pass ing through a stuffing-box at one end of the chamber G. Upon this rod are adjustable nuts i and twopieces of rubber or other elastic material, j, one upon the outside and the other upon the inside of V the outer end of the bridle I, for the purpose of arresting the movement of the valve F at the proper moment and preventing the valve from striking against the ends of its chamber.

To prevent the valve F from turning in its chamber, the connecting-piece d of the valve may be provided with a slot, 70, and a bolt may be passed through the valve-chamber and such slot k.

IV hen steam is first admitted at either end of the cylinder, and before the position of the valve F has been changed in its chamber, live steam can pass for a moment into the valvechamber G. To prevent waste of steam, I provide the port H with a check-valve, Z, which is held open by a spring, in, which spring is suftieiently strong to prevent the valve Z from being closed by the exhaust-steam, but not sufficiently strong to resist the action of live steam which may pass into the valve-chamber G;

hence when live steam does pass into such chamberits pressure will close the valve Z and prevent waste. As soon as the position of the valve F has been changed the passage of live steam to the chamber G will be cut off, and then the spring 1% will open the valve Z, allowing the exhaust-steam to escape.

The operation is as follows: Suppose the piston to be moving in the direction of the arrow, steam having been cut oil, and the exhaust-port a being closed by thevalve D, the valve F at the same time having been brought to the position shown in Fig. 1 by the action of steam admitted to the valve-chamber through the passage h, the parts being in this position, the exhaustpassage 6, leading into the valve-chamber G, will be open, and the steam remaining in the cylinder in front of the piston will pass out through the exhaust-passage e and through the valve-chamber G, and out at the exhaustport H. lVhen the piston has completed its ICO' IO gine will be relieved from the labor of workleft-hand end of the cylinder, after the exhaust port a has been closed, will pass out through the passage 6 into the chamber G and out at the exhaust-port H. In this manner the ening against and compressing the large quantity of steamremaining in the cylinder in front of the piston after the usual exhaustpassages have been closed.

If desired, the movement of the slide-valve D can be so adjusted that steam will be admitted to the cylinder just before the piston reaches the end of its stroke, which admitted live steam will serve the purpose of a cushion.

As shown, theexhaust-passages e e communicate with the passages a a; but such passages e 6 might be made to communicate with the cylinder at any other suitable point. The size of the passages e e and h h must be adapted to the engine with which they are to be used. h h may be considerably smaller than c e.

I do not limit myself to the precise arrangement of the parts which is shown in the drawings, nor to the exact construction shown.

What I claim as new, and desire to secure by Letters Patent, is-

1. In combination with a steam-cylinder provided with a valve and inlet and exhaust passages, as usual, a secondary valve located in a chamber provided with an exhaust-outlet, and

Y passages e 6 leading from the cylinder to such i secondary valve-chamber for the purpose of allowing steam to exhaust from the cylinder after the ordinary exhaust-port has been closed, substantially as and for the purpose specified. 2. In combination with a steamcylinder provided with a valve and inlet and exhaust passages, as usual, a secondary valve located in a chamber provided with an exhaust-outlet, and passages e 6, leading from the cylinder to such secondary valve-chamber, and passages h 71/, leading from the cylinder to the ends of the secondary valve-chamber, substantially as and for the purposes specified. I

, AARON A. AOKERLY. Witnesses:

E. A. Wnsr, ALBERT H. ADAMS. 

